Fixed crash if initialization of EGL failed but was tried again later.

The internal function SDL_EGL_LoadLibrary() did not delete and remove a mostly
uninitialized data structure if loading the library first failed. A later try to
use EGL then skipped initialization and assumed it was previously successful
because the data structure now already existed. This led to at least one crash
in the internal function SDL_EGL_ChooseConfig() because a NULL pointer was
dereferenced to make a call to eglBindAPI().

test/COPYING

@@ -0,0 +1,8 @@
+
+The test programs in this directory tree are for demonstrating and
+testing the functionality of the SDL library, and are placed in the
+public domain.
+
+October 28, 1997
+--
+	Sam Lantinga				(slouken@libsdl.org)